Apparatus for making two-sided copies from two images on an original

ABSTRACT

TWO IMAGES FROM AN ORIGINAL ARE PLACED ON AN ENDLESS BELT 10. THE FIRST IMAGE IS XEROGRAPHICALLY TRANSFERRED TO ONE SIDE OF THE COPY PAPER 31. THE COPY PAPER IS NEXT TURNED OVER AS FOLLOWS. THE COPY IS FED PAST A SET OF ROLLERS 36, 37 AWAY FROM THE PATH OF BELT 10. AN AIR BLAST URGES THE COPY TO ANOTHER BELT 39. THE COPY SHEET MOVES ALONG BELT 39 UNTIL IT AGAIN MEETS THE MAIN BELT 10. AFTER THE COPY SHEET HAS BEEN REVERSED, THE SIDE WITHOUT THE FIRST IMAGE CAN RECEIVE THE SECOND IMAGE.

June 27, 1972 c. ALTMANN 3,672,765

APPARATUS FOR MAKING T SIDED COPIES FROM TWO IMAGES ON ORIGINAL Filed Aug. 5, 1970 2 Sheets-Sheet l CONRAD ALTMANN INVENTOR.

BY A, Jwu fiaxwm h 7 ATTORNEYS June 27, 1972 c ALTMANN I 3,672,765

APPARATUS FOR MA KING TWO-SIDED COPIES FROM TWO IMAGES ON AN ORIGINAL Filed Aug. 5, 1970 I 2 Sheets-Sheet 2 Ll- I m 50 CONRAD ALTMANN INVENTOR. S' I W BY W ATTORNEYS United States Patent Oflice Patented June 27, 1972 3,672,765 APPARATUS FOR MAKING TWO-SIDED COPIES FROM TWO IMAGES ON AN ORIGINAL Conrad Altmann, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, NY.

CTltinuagon-lirgiagart T1115 application Ser. No. 716,092,

ar. s a cation Au 3 1970 Ser. No. 60,500 PP g Int. Cl. G03b 15/00 US. Cl- 355-24 22 Claims ABSTRACT OF THE DISCLOSURE Two images from an original are placed on an endless belt 10. The first image is xerographically transferred to one side of the copy paper 31. The copy paper is next turned over as follows. The copy is fed past a set of rollers 36, 37 away from the path of belt 10. An air blast urges the copy to another belt 39. The copy sheet moves along belt 39 until it again meets the main belt 10. After the copy sheet has been reversed, the side without the first image can receive the second image.

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-impart application of commonly assigned copending US. application Ser. No. 716,092 to Conrad Altmann, entitled Apparatus for Making Two-Sided Copies From Two-Sided Originals, filed Mar. 26, 1968, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to a reversing device, and more particularly to a device for reversing a receiver for placing images on opposite sides thereof.

Description of the prior art Most electrophotographic machines permit printing an image on only one side of a receiver sheet. Thus, when two sides of an original are to be copied, the duplicate requires two sheets to hold the same information. Thus, the copies are not as easy to handle and there is always a possibility that the additional sheets may be lost. In addition, the large number of pages required for a copy may be excessive if the original comprises several pages printed on both sides.

A system for printing on both sides of a receiver is shown in US. Pat. No. 3,318,212 to Rubin wherein both sides of an original are scanned and the images placed on a rotating xerographic drum. The images are toned and sequentially transferred to an intermediate drum. One of the two images is transferred to a third drum and then the remaining image on the intermediate drum and the image on the third drum are transferred to opposite sides of a receiver which is passed therebetween to provide a finished copy. However, since one of the images is transferred one more time than the other image, there is the possibility that the two images on opposite sides of the receiver will be of different densities, which may be undesirable in some instances. This could be compensated for by using different exposure levels for each side, but this would add to the cost and complexity of the device. Furthermore, exposure is made by scanning which requires precise synchronization between the scanning mechanism and the rotating xerographic drum.

SUMMARY OF THE INVENTION In the present invention, at least two images are projected from an original onto a reproduction apparatus,

such as a charged photoconductive element or member in the form of an endless photoconductive belt. The belt may be stopped during exposure, as with a slack loop arrangement, or an electronic flash may be used to make the exposures while the belt is moving. The images are then toned and one image is transferred to one side of a receiver. The receiver is then turned over by a novel reversing mechanism and a second image transferred to the opposite side of the receiver and fused. Since there are no intermediate transfers of the image before printing, the density and hence the quality of the image can be maintained more commensurate with the density and quality of the original image. Also the density of the image on the opposite side of the receiver should be substantially the same. In a first embodiment, the images are projected from opposite sides of an opaque original whereas in a second embodiment adjacent images are projected from an original to be copied on opposite sides of a receiver.

Additional novel features of the invention will become apparent from the description which follows, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal section of an electrophotogr-aphic apparatus showing a reversing device constructed in accordance with this invention;

FIG. 2 is a perspective view of a first optical system which may be utilized with the apparatus of FIG. 1;

FIG. 3 is a fragmentary plan view of a section of microfilm having adjacent images arranged in one format;

FIG. 4 is a fragmentary plan view of another section of microfilm having adjacent images arranged in another format; and

FIG. 5 is a perspective view of a second optical system which may be utilized 'with the apparatus of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with this invention, the electrophotographic apparatus A of FIG. 1 includes an endless photoconductive belt 10 which includes a photoconductive layer on a conductive backing and is driven by suitable means, such as motor 11 past a charging station 12, an exposure station 13, through a toning station 14, past transfer means such as a first transfer station 15 and a second transfer station 16, a cleaning station 17 and an erase lamp 18. With the exception of the exposure station, all the other stations may be of any suitable type known in the prior art, the construction thereof not being a part of this invention.

In the embodiment of FIG. 2, the optical system S for flash exposure at station 13 includes plane mirrors 20 and 21 which project the images from opposite sides of original document 22, mounted in supports 23, through lenses 24 and 25, respectively. The light which forms these images is then reflected off of plane mirror 26 onto photoconductive belt 10 to form electrostatic images 27 and 28, respectively. Of course, mirror 26 could be two separate mirrors rather than a single mirror, as shown, or could be omitted entiely if the optics are rotated so that the images are projected directly onto the photoconductive belt from lenses 24 and 25.

As belt 10 moves in a counterclockwise direction, as viewed in FIG. 1, images 27 and 28 will be toned at toning station 14 and fed to the first transfer station 15. At the same time, a receiver sheet 31 is fed from a hopper 32 by a feed mechanism, such as roller 33, through metering rollers 34 and support rollers 35 to transfer station 15. Thus, image 28 is transferred from photoconductor to receiver 31. The receiver is then directed upwardly by deflector 29 through a pair of rollers, such as fusing rollers 36 and 37, into a receiver reversing means R. Means, such as a compressed air nozzle or air puffer 38, may be activated by suitable means (not shown) to force the receiver against a reverse driving means, such as endless belt 39 which extends between rollers 40 and 41, and cooperates with fusing roller 36 to feed the receiver into position to be brought into contact with photoconductor 10 as it passes between belt 39 and roller 42. As can be seen from FIG. 1, the receiver is turned over so that the opposite side is brought into contact with photoconductor 10 to receive image 27.

In the meantime, photoconductor 10 has been fed downwardly past roller 43 around a roller 44, the diameter and spacing of this roller being such that by the time the receiver is reversed by reversing mechanism R, the second image 27 on the photoconductor will be in position to be transferred to the second side of the receiver at the second transfer station 16. The receiver is then deflected by deflector 30 so that this second image is fused by fusing rollers 45 and 46 after being separated from the photoconductor, as shown. Finally, receiver 3-1 is fed to a copy receptacle 47. The photoconductor continues to move in a counterclockwise direction, any remaining toner thereon from images 27 and 28 being removed at cleaning station 17 and any remaining electrostatic charge pattern being erased by exposure to erase lamp 18.

An original having images side by side which are to be projected may be utilized, such as microfilm 50 of FIG. 3 which includes pairs of spaced images, such as images 51 and images 52 which are arranged side by side, as shown. An alternative format is shown in FIG. 4 wherein a microfilm strip 50' includes pairs of side by side images 53 and 54, as shown.

An exposure station S for projecting microfilm images is shown in FIG. 5, wherein microfilm 50 is fed from a supply reel 56 past a projection gate defined by spaced rollers 58 and 60 to a take-up reel 62. A light source 64 together with lens 65 uniformly illuminates the images on microfilm 50 so that they are projected by means of a projection lens 66 to a movable mirror 68 which may be brought into the light path to project light onto screen 70 so that the images may be viewed. Conveniently, the screen is provided with image field marks 72 so that the images may be centered on the screen prior to printing. After centering, mirror 68 is moved out of the projection beam by means (not shown) so that the projection lens now projects the image onto mirror 74 which reflects the images in spaced positions along photoconductor 10, as shown. Although the projection lens has been illustrated as a single lens 66, this lens can take any form so long as it is constructed so as to project the images onto the photoconductor at the proper spacing for development and transfer to opposite sides of the receiver sheet in the device shown in FIG. 1. For example, projection lens 66 might take the form of two rotatable lenses which include dove prisms to allow image rotation and one of the lens may be moved in a longitudinal direction of the film to allow adjustment of the image spacing. With such an arrangement, it is apparent that the spaced images 51 or the spaced images 52 as shown in FIG. 3 could be projected or alternatively images arranged in the format of FIG. 4 such as images 53 and 54 could be projected, respectively. Also, the device could be used to project images arranged in other formats. A similar projection system could be used to project adjacent images on.an opaque original or the images to be projected may be spaced from each other rather than being side-by-side.

From the foregoing, it will be apparent that the novel features of this invention and the advantages thereof have been achieved. A means has been provided wherein an exposure can be made eitherby scanning or by flash exposure and the two electrostatic images, thus formed can be developed and sequentially transferred to a re ceiver which is reversed by reversing mechanism after the first transfer. The transfers are made directly from the photoconductor to the receiver without any intermediate steps.

The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

I claim:

1. In an electrophotographic apparatus having a movable photoconductive member, an exposure station for exposing one side of the photoconductive member to separate images projected from an original document to be copied to form separate electrostatic images on said one side of said photoconductive member, a toning station for developing said electrostatic images, a first transfer station for transferring one developed image to one side of a receiver and means for moving said photoconductive member past said stations, the improvement comprising:

means for reversing said receiver after passing through said first transfer station to position the other side of said receiver to receive the second image from said photoconductive member; and

a second transfer station for transferring said second image to said other side of said receiver;

said means for reversing said receiver including a reverse driving means for feeding said receiver to said second transfer station with said other side positioned to receive said second image; means for feeding said receiver from the first transfer station into said reverse driving means; and means for urging said receiver into engagement with said reverse driving means.

2. An electrophotographic apparatus, as claimed in claim 1, wherein said photoconductive member includes:

a flexible endless belt.

3. An electrophotographic apparatus, as claimed in claim 1, wherein:

said reverse driving means includes an endless belt; and

said feeding means includes a pair of fusing rollers for fusing said first image to said receiver, one of said rollers being positioned adjacent said endless belt to cooperate therewith to feed said reversed receiver to said second transfer station.

4. An electrophotographic apparatus, as claimed in claim 1, wherein the improvement further includes:

photoconductor diverting means between said first and second transfer stations for directing said photoconductor away from said receiver during reversal of said receiver to bring said second image on said photoconductor into position to be transferred to said other side of said receiver after said receiver is reversed.

5. An electrophotographic apparatus having a photoconductive member movable past a series of electrophotographic stations to form images on opposite sides of a receiver from an original having first and second images thereon, said apparatus comprising:

a charging station for placing a substantially uniform electrostatic charge on said photoconductive member;

an exposure station for projecting said first and second images from the original at spaced positions along said photoconductive member to form spaced first and second electrostatic imagesthereon;

a developing station for toning said first and second electrostatic images;

a first transfer station for transferring said first toned image to one side of the receiver;

means for reversing the receiver after passing through said first transfer station to position the other side of the receiver to receive said second toned image;

a second transfer station for transferring said second toned image to said other side of the receiver; and

means for moving said photoconductive member past said receiver.

6. An electrophotographic apparatus, as claimed in claim 5, wherein said exposure station includes:

means for projecting said first and second images from opposite sides of original.

7. An electrophotographic apparatus, as claimed in claim 5, wherein said exposure station includes:

means for projecting said first and second adjacent images from the original.

8. For use in electrophotographic apparatus of the type having a photoconductor surface movable repetitively around an endless operative path past a plurality of operative stations, an improved transfer electrophotography method for producing copy images on opposite sides of a copy sheet, said method comprising:

(a) moving the photoconductor surface around the endless path;

(b) charging, exposing and developing the moving photoconductor surface to form on said surface leading and trailing toner images that are spaced with respect to each other in a direction along said operative path;

(0) feeding a copy sheet so that a first side thereof passes in transfer relation with said leading toner image on said moving photoconductor surface;

(d) transferring said leading toner image to said first side of said copy sheet;

(e) feeding said copy sheet out of transfer relation with said photoconductor surface, inverting said copy sheet while out of contact with said photoconductor surface and feeding said copy sheet so that the side of said copy sheet opposite said first side passes in transfer relation with said trailing toner image on said moving photoconductor surface; and

(f) transferring said trailing toner image to said op posite side of said copy sheet.

9. The invention defined in claim 8 further comprising the steps of:

fusing said leading toner image onto said first side of said copy sheet after transfer of said leading toner image thereto and prior to inverting said copy sheet and fusing said trailing image to said opposite side of said copy sheet after transfer of said trailing toner image thereto.

10. The invention defined in claim 8 wherein said exposing step includes simultaneously projecting light images from opposite sides of a substantially opaque original onto spaced areas of said photoconductor surface.

11. The invention defined in claim 8 wherein said exposing step includes simultaneously projecting light images of transparencies onto spaced areas of said photoconductor surface.

12. The invention defined in claim 8 further including the step of delaying the movement of said trailing toner image past the operative stations of the apparatus between transfer of said leading and trailing toner images.

13. Improved electrophotographic apparatus for producing copy images on both sides of a copy sheet, said apparatus comprising:

(a) a photoconductor surface repetitively movable around an endless operative path;

(b) means for moving the photoconductor surface around said endless operative path;

(c) means, located along said path, for charging, ex-

posing and developing successive sections of said moving photoconductor surface to form on said surface, leading and trailing toner images which are spaced with respect to each other in a direction along said operative path;

(d) means, located proximate said operative path, for feeding a copy sheet toward said operative path in a manner such that a first side of the fed copy sheet passes in transfer relation with the leading toner image formed on said photoconductor surface;

(e) first transfer means, located along said operative path, for transferring the leading toner image to the first side of the fed copy sheet;

(f) means for feeding the copy sheet out of transfer relation with said photoconductor surface, inverting the copy sheet while out of contact with said photo conductor surface and feeding the copy sheet back toward said operative path in a manner such that the side of the copy sheet opposite the first side passes in transfer relation with the trailing toner image formed on said moving photoconductor surface; and

(g) second transfer means, located along said operative path downstream from said first transfer means, for transferring the trailing toner image to the opposite side of the copy sheet.

14. The invention defined in claim 13 further comprising:

first means for fusing the leading toner image onto the first side of the copy sheet after transfer of the leading toner image thereto and prior to inverting the copy sheet and second means for fusing the trailing image to the opposite side of the copy sheet after transfer of the trailing toner image thereto.

15. The invention defined in claim 13 wherein said exposing means includes means for simultaneously projecting light images from opposite sides of a substantially opaque original onto spaced areas of said photoconductor surface.

16. The invention defined in claim 13 wherein said exposing means includes means for simultaneously projecting light images of transparencies onto spaced areas of said photoconductor surface.

17. The invention defined in claim 13 further including means for delaying the movement of the trailing toner image past the operative stations of the apparatus between transfer operations on the leading and trailing toner images.

18. Improved electrophotographic apparatus for producing copy image on both sides of a copy sheet, said apparatus comprising:

(a) a photoconductor surface mounted for movement within said apparatus around an endless operative path past the electrophotographic stations of said apparatus, said surface being of sufficient length to provide at least two successive discrete imaging areas spaced for sequential movement past an operative station of said apparatus;

(b) means for moving said photoconductor surface around said operative path;

(c) means for charging the imaging areas on said photoconductor surface;

(d) means for exposing each imaging area on said photoconductor surface to a separate radiation pattern;

(e) means for developing each imaging area to form leading and trailing toner images;

(f) means for transferring a toner image from an imaging area of said photoconductor surface to a copy sheet in transfer relation therewith;

(g) means for feeding a copy sheet past said transfer means with a first side in transfer relation with the leading toner image on said photconductor surface;

(h) means for feeding the copy sheet away from said path, inverting the copy sheet and feeding the copy sheet past said transfer means with the side opposite said first side in transfer relation with the trailing toner image; and

(i) means for fusing the toner images onto said copy sheet.

19. The invention defined in claim 18 wherein said fusing means is located adjacent said transfer means for fusing the leading and trailing toner images to the copy sheet immediately after their respective transfers to the sheet.

20. The invention defined in claim 18 wherein said transfer means includes first and second transfer stations spaced along the operative path and respectively operative on the leading and trailing toner images and wherein said fusing means includes first and second fusers respectively associated with said first and second transfer stations and operative respectively on the leading and trailin toner images.

21. The invention defined in claim 18 further including means for delaying movement along said path of the imaging area bearing the trailing toner image While said copy sheet inverting means is inverting the copy sheet.

22. The invention defined in claim 18 wherein said exposing means includes means for simultaneously projecting the radiation patterns onto the leading and trailing imaging areas.

References Cited UNITED STATES PATENTS Schubert 355-23 Magnusson 355-16 X Burkhardt 271-R.D. Dig. Klingler 271-74 X Lohner 355-24 Bhagat 355-26 X Drawe 3.55-25 X Lagonegro 271-3 SAMUEL S. MATTHEWS, Primary Examiner M. HARRIS, Assistant Examiner US. Cl. X.R.

271-74, R.D. DIG; 355-16 

